136 Transactions of the Roijal Microscopical Society. 
gives a good account of the anatomy of ants, especially with 
reference to the digestive and reproductive organs. The cephalic 
ganglia, as already mentioned, have been described by Leydig and 
Rabl Ruckhard, but no one has yet described the muscular system, 
to which therefore I have specially directed my attention. 
According to Burmeister, the antennas in insects “ have three 
muscles which move them — an extensor, which originates from the 
forehead in front of the eyes, and affixes itself to the exterior 
margin of the basal joint ; a flexor, which originates from the 
anterior apex of the inside of the skull, and affixes itself to the 
inner margin of the basal joint ; and an elevator, which originates 
exteriorly contiguous to the extensor from the margin of the eye, 
and inserts itself at the lower margin of the basal joint.” 
This description, which is given as applicable to insects gene- 
rally, appears to be founded mainly on Strauss-Durckheim’s account 
of Melolontha. It certainly, however, does not apply to Formica, in 
which two of the muscles arise, not directly from the skull itself, but 
from the lateral branches of the antero-posterior cranial apophysis. 
Plate CLXXXIX., Fig. 1, A 1 and A 2, Fig. 2, A 1 and A 2. 
It would be very interesting to work out the gradual stages 
through which this remarkable difference was effected. 
One of these muscles draws the antenna forwards, the hinder 
one outwards. There is also a smaller muscle which draws the 
antenna backwards and upwards. Below the attachment of the 
antenna is a chitinous process (Plate CXCI., Fig. 1, R), which is free 
at the lower end, while at the base of the antenna it divides into 
two branches, which are attached to the lower ring of the antenna. 
The more or less flexible portion of this rod is bent when the 
antenna’s muscles contract, and when they relax the elasticity of 
the rod at once brings the antenna back into its normal position. 
This mechanism, therefore, differs very much from that of 
Melolontha, and from the general descriptions given by Bur- 
meister. Mr. Busk, who has been good enough to look through 
my preparations with me, concurs in the above view. 
The mouth, as will be seen in Plate CLXXXIX., Figs. 1 and 3, 
opens immediately above the labium, or lower lip. Various opinions 
have been entertained by different naturalists as to the true position 
of the mouth in Hymenoptera. Swammerdam considered the 
proboscis of bees as their mouth, regarding it as a tube through 
which liquid was sucked up. He recognized, however, that wasps 
had another channel through which they took in nourishment. 
Reaumur thought that in wasps the mouth was situated on the 
under side of the proboscis. Latreille appears to have mistaken 
the entrance into the salivary duct for the mouth. Treviranus, 
like Swammerdam, regarded the proboscis of bees as a hollow tube, 
through which fluid could be sucked up. I merely refer to these 
